1. Introduction Lipoprotein(a), or Lp(a), is a type of lipoprotein that is structurally similar to LDL (low-density lipoprotein) but carries an additional protein called apolipoprotein (a). 2. Purpose of the Study The primary purpose of this study is to investigate the effect of Lp(a) levels on arterial stiffness, endothelial function, and left atrial (LA) and left ventricular (LV) deformation over a 12-month follow-up period. Secondarily, the study will investigate: * a) The incidence of major adverse cardiovascular events (MACE), including cardiovascular death, acute myocardial infarction, and acute stroke. * b) The correlation between MACE incidence and parameters of arterial stiffness, endothelial function, and LA/LV deformation. * c) The levels of oxidative load markers. 3. Materials and Methods This observational study will include adults aged 18-75 years (regardless of gender) who visit the outpatient clinics of the 2nd University Cardiology Clinic at Attikon General Hospital. All participants will sign a consent form. A full medical history, clinical examination, and blood collection will be performed to determine levels of Total Cholesterol, LDL-C, HDL-C, triglycerides, and Lp(a) at each visit.. Participants will be divided into three groups: * Group A: Lp(a) ≥50 mg/dL with Total Cholesterol\<200 mg/dl * Group B : Lp(a) \<50 mg/dL. with Total Cholesterol\>200 mg/dl * Group C (Control): Lp(a) \<50 mg/dL. with Total Cholesterol\<200 mg/dl At each group n ≥ 100 participants are anticipated. Measurements at baseline, at 6 and at 12 months: * Arterial Stiffness: Determination of carotid-femoral pulse wave velocity (cf-PWV) using the Complior SP device and 24-hour pulse wave analysis with the Mobil-O-Graph device. * Endothelial Function: Measurement of the endothelial glycocalyx thickness of sublingual capillaries using a Sidestream Dark Field (SDF) camera (GlycoCheck). This is expressed through the perfused boundary region (PBR) index. * Cardiac Deformation: Use of two-dimensional strain (speckle tracking) to calculate the Global Longitudinal Strain (GLS) of the LV and LA strain. * Oxidative Load: Determination of malondialdehyde (MDA) and protein carbonyls (PCs) levels as markers of oxidative stress using spectrophotometric kits. Statistical Analysis: Comparisons regarding the changes in these markers over 6 and 12 months will be conducted between the three groups.